Linkage binding

ABSTRACT

A linkage binding for coupling a user&#39;s shoed or booted foot to another object, such as a ski or snowshoe. The linkage binding may include an upper plate including an upper surface to which a user&#39;s shoed or booted foot is to be secured, a lower plate including a lower surface to which another object is to be secured, a front connecting link hingedly attached to both the upper plate and the lower plate, and a rear connecting link hingedly attached to both the upper plate and the lower plate to form a 4-bar linkage.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to a linkage binding configured to facilitate a walking or running motion between a user's foot and an object (e.g., ski, snowshoe, or the like).

Background and Related Art

There exists a fundamental need to couple a person's foot to an object in a manner that facilitates a natural walking or running motion. There are many instances where objects may be affixed to a person's feet. In many of these instances a certain range of motion between the foot and object is beneficial or necessary, especially when the object is large enough that it inhibits natural movement. There may also exist a need to restrict movement between the foot and object along one or more other axes to facilitate directional control and placement of the object. In the most common scenario, it may be desired to have a degree of rotational freedom about a left to right axis at the user's toe while maintaining lateral and torsional rigidity between the foot and object. This style of object connection is for example, realized in a cross country nordic ski binding. There have been two fundamental approaches to realizing this motion. One is to immovably couple the toe of a boot with a flexible sole to the object, allowing the flex in the boot to accommodate the walking motion. The second approach is to connect a rigid or semi-rigid boot to the object via an axial connection in the left to right orientation in the region of the toe, allowing an arcing motion to occur through the heel, reproducing the walking motion.

SUMMARY OF THE INVENTION

The present disclosure relates to an improved method of fixing an object to the foot while facilitating a natural walking motion to occur between the foot and the object, as well as to structures enabling such fixation. In particular, the present linkage bindings may be configured as an insert between alpine downhill skis and alpine downhill ski boots, where the heel of the boot is fixed in the downhill ski binding. The selectively insertable linkage binding allows the heel of the alpine boot to freely rotate upwards away from the downhill ski so as to better accommodate a walking motion (e.g., uphill), all while maintaining coupling (indirectly—through the linkage binding) between the alpine boot and the alpine (i.e., downhill) ski. Portions of the linkage can also be incorporated into a boot (or other footwear) and/or a ski, snowshoe, or other item to be attached to the foot. For example, a lower plate (as will be explained below) may be incorporated into a ski or snowshoe, an upper plate incorporated into a boot or other footwear, or the like.

In at least some embodiments, the improved connection method can be achieved via the use of four fundamental components. These are: an upper plate, a lower plate, and two connecting links. The upper plate may allow for a foot or footwear to be securely attached. The lower plate may serve as an attachment point to securely affix the object (e.g., ski, snowshoe, etc.). The upper plate and lower plate may be attached to each other via the two links, each link may be fastened via rotational connections at each end, creating what is known as a four bar linkage. This arrangement constrains the movement of the upper plate in relation to the lower plate to within a path that is determined by the arrangement of the four bar linkage. In light of the present disclosure, it will be apparent to those skilled in the art that a wide range of motions can be obtained by altering the geometry of the four bar linkage (e.g., connection points of the connecting links to the plates, lengths of the connecting links, and the like).

It will be appreciated that the linkage can be separate from a provided boot (or other footwear) and a ski (or snowshoe, or other item to be attached to the user's foot). In some embodiments, portions of the linkage may be incorporated into a boot, ski, or the like. For example, the upper plate may be incorporated into a ski boot or other footwear. The lower plate may be incorporated into a ski, snowshoe, or the like.

Further features and advantages of the present invention will become apparent to those of ordinary skill in the art in view of the detailed description of preferred embodiments below.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the manner in which the above recited and other features and advantages of the present invention are obtained, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. Understanding that the drawings depict only typical embodiments of the present invention, the present invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 illustrates a representative linkage binding;

FIG. 2 shows a representational linkage binding connecting a foot to the upper plate and an object to the lower plate;

FIG. 3a illustrates representational linkage binding with the upper plate at an angle of 0° in relation to the bottom plate;

FIG. 3b illustrates representational linkage binding with the upper plate at an angle of 15° in relation to the bottom plate;

FIG. 3c illustrates representational linkage binding with the upper plate at an angle of 30° in relation to the bottom plate;

FIG. 3d illustrates representational linkage binding with the upper plate at an angle of 45° in relation to the bottom plate;

FIG. 3e illustrates representational linkage binding with the upper plate at an angle of 60° in relation to the bottom plate;

FIG. 4a illustrates a representational linkage binding hinging at or near the heel;

FIG. 4b illustrates a representational linkage binding in the neutral stance;

FIG. 4c illustrates a representational linkage binding hinging at or near the toe;

FIG. 4d is a further illustration of the configuration seen schematically in FIGS. 4a -4 c;

FIG. 5 illustrates a more detailed exemplary embodiment of a linkage binding;

FIG. 6 illustrates an exemplary embodiment of a linkage binding in use with a DIN type sole alpine ski boot;

FIG. 7 illustrates an exemplary embodiment of a linkage binding with reconfigurable upper plate and lower plate;

FIG. 8a illustrates a representational linkage binding with the upper plate configured to attach ski boots via a releasable binding for downhill skiing in a closed position;

FIG. 8b illustrates a representational linkage binding with the upper plate configured to attach ski boots via a releasable binding for downhill skiing in an open position;

FIG. 9a illustrates a representational linkage binding in an open position with no limit set on the angular relation of the upper and lower plate;

FIG. 9b illustrates a representational linkage binding in a closed position with no limit set on the angular relation of the upper and lower plate;

FIG. 9c illustrates a representational linkage binding in an open position with the angular relation of the upper and lower plate restricted by 8 degrees;

FIG. 9d illustrates a representational linkage binding in a closed position with the angular relation of the upper and lower plate restricted by 8 degrees;

FIG. 9e illustrates a representational linkage binding in an open position with the angular relation of the upper and lower plate restricted by 15 degrees;

FIG. 9f illustrates a representational linkage binding in a closed position with the angular relation of the upper and lower plate restricted by 15 degrees;

FIG. 10 illustrates another embodiment of a linkage binding, similar to that shown in FIGS. 5-7;

FIG. 10A illustrates a close up view of the lifters and the rear of the upper plate of FIG. 10A;

FIG. 11 illustrates another embodiment of a linkage binding, similar to that of FIG. 10, but in which only a single front pin hinge is provided, which slides within a slot (i.e., what some refer to as an infinite length 4-bar linkage); and

FIG. 12 schematically illustrates the virtual pivot point associated with the linkage binding.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an exemplary linkage binding 100 according to at least one embodiment. The linkage binding 100 can be created via the use of four components. These are: an upper plate 1, a lower plate 2, and front connecting link 3 and a rear connecting link 4. The upper plate 1 may have a top surface 5 where a foot or footwear may be securely attached. The lower plate 2 may have a lower surface 6 that can serve as an attachment point to securely affix an object such as a ski, snowshoe, or other object to be coupled to a foot. It will be appreciated that in some embodiments, upper plate 1 could be incorporated into a boot or other footwear (e.g., the boot or other footwear could function as upper plate 1, where the boot or footwear were designed as such). For example, a pin-system touring ski boot could be configured such that the boot itself included, or was, the upper plate 1. Similarly, lower plate 2 may be the object itself (e.g., a ski or snowshoe). For example, a boot may be provided, which connects directly to a touring ski via the two connecting links exclusively (i.e., the lower and upper plates are incorporated into the boot and the ski, respectively). Such a configuration would allow the benefits of the presently disclosed linkage to be applied to lightweight touring or cross-country skis, as well as the adapter or insert for converting a downhill ski system, as principally described herein. Such embodiments are within the scope of the present disclosure.

The upper plate 1 may be rotationally coupled to the front connecting link 3 via hinge 7 (e.g., a pin hinge). The upper plate 1 may also be rotationally coupled to the rear connecting link 4 via hinge 8 (e.g., a pin hinge). The lower plate 2 may be rotationally coupled to the front connecting link 3 via hinge 9 (e.g., a pin hinge). The lower plate 2 may also be rotationally coupled to the rear connecting link 4 via hinge 10 (e.g., a pin hinge).

This arrangement creates what is known as a four bar linkage. The position of hinges 7 and 8 along upper plate 1 and hinges 9 and 10 along lower plate 2, along with the length of front connecting link 3 and rear connecting link 4 may be positioned so that a walking motion is reproduced, or accommodated within a user.

FIG. 2 shows an exemplary embodiment of linkage binding 100 in the context of a boot 11 and an object 12 (e.g., a ski). The boot 11 is fastened to the linkage binding 100 via top surface 5. The object 12 is fastened to the linkage binding 100 via bottom surface 6.

FIG. 3a shows an exemplary embodiment of linkage binding 100 with upper plate 1 at an angular position of 0° relative to lower plate 2. This may represent the position of the linkage binding 100 while the user is standing in place, not walking, or is transitioning between steps.

FIG. 3b shows an exemplary embodiment of linkage binding 100 with upper plate 1 at an angular position of 15° relative to lower plate 2. This may represent the position of the linkage binding 100 near the beginning or ending of a step.

FIG. 3c shows an exemplary embodiment of linkage binding 100 with upper plate 1 at an angular position of 30° relative to lower plate 2. This may represent the position of the linkage binding 100 mid-step.

FIG. 3d shows an exemplary embodiment of linkage binding 100 with upper plate 1 at an angular position of 45° relative to lower plate 2. This may represent the position of the linkage binding 100 mid-step.

FIG. 3e shows an exemplary embodiment of linkage binding 100 with upper plate 1 at an angular position of 60° relative to lower plate 2. This may represent the position of the linkage binding 100 at or near a maximum extension.

FIG. 4a shows an exemplary embodiment of linkage binding 100 in which the links 3 and 4 may be approximately the same length as one another and attached at either end of the upper plate 1, crossing one another to attach at the opposite end of the lower plate 2. This scissor type arrangement creates a center of rotation that rapidly shifts from front to rear. The linkage binding 100 is shown in a position of rotation from the rear, at the moment of heel strike in a walking or running stride.

FIG. 4b shows an exemplary embodiment of linkage binding 100 in a neutral position. This may be the position of standing or transitioning during a walking or running stride.

FIG. 4c shows an exemplary embodiment of linkage binding 100 in a position of rotation from the front, e.g., at the moment of toe-off in a running stride.

FIG. 5 shows an exemplary embodiment of linkage binding 100 in which the front connecting link is positioned at or near the front end of the upper plate, and to a more rearward point on the lower plate. The front link may be less than ⅓rd the length of the rear link, which is acutely positioned from the rear end of the lower plate, to a point behind the front link's connection on the upper plate. The intersection point found by following the links along their length is located at the ball of the user's foot, creating an instantaneous center of rotation that follows a more natural path than what is possible with a single fixed rotational point. FIG. 4d shows a further example of such an arrangement. For example, in some embodiments, front link 3 may be less than about 40%, less than about 35%, less than about 33%, less than about 30%, less than about 25%, or less than about 20% of the length of rear link 4.

Linkage binding 100 creates a virtual pivot point associated with the linkage binding 100 at an intersection of the front linkage 3 with the rear linkage 4. It will be apparent that the lengths of the links 3 and 4, as well as those of upper and lower platforms 1 and 2, and the attachment points (7, 8, 9, and 10) between platforms and links together determine the particular location of the virtual pivot point. Such a virtual pivot point may advantageously be located near the ball of the user's foot when a user's foot is secured to the linkage binding (e.g., using a boot). For example, the virtual pivot point may be within about 3 cm, within about 2 cm, within about 1 cm of the location corresponding to the ball of the user's foot, as shown in FIG. 12. Because the links 3, 4 and platforms 1, 2 move as the user progressively takes a step, the virtual pivot point (or center of rotation C_(R) in FIG. 12) moves constantly, throughout such movement. The pathway defined by the virtual pivot point is an ellipse, as will be appreciated by those of skill in the art. FIG. 12 illustrates such concepts, showing the plane of link 3 (P₃), the plane of link 4 (P₄), and the resulting elliptical pathway (P_(E)).

FIG. 5-7 show an exemplary embodiment of a linkage binding 100 configured so that it may serve as an insert between a regular downhill ski binding and a regular downhill ski boot, adapting the system for uphill travel (e.g., walking uphill) by allowing the boot to hinge upward from the toe while in the binding. In certain embodiments, upper plate 1 is configured with a toe binding 13 and a heel binding 14 and a selectively engageable clamp 15 so that a regular downhill ski boot may be removably and rigidly coupled to top surface 5. In certain embodiments, the position of the heel binding may be relocated by the user so that a range of different size ski boots may be fit. For example, holes 22 in rear section 17 of lower plate 2 allow a user to insert pin 10 and or 10 a in desired holes 22, so as to accommodate a variety of boot sizes. In an example, such adjustability may accommodate boot sizes from 22 to 31.5 (e.g., on a MONDOPOINT scale (e.g., comfort fit or performance fit scales). In an embodiment, the holes 22 may be positioned every 5 mm, so that adjacent holes correspond to half-size incremental adjustments. It will be appreciated that smaller or larger sizes could also be accommodated, as needed. Heel and toe bindings 13 and 14 may be configured to flex somewhat under tension, so as to accommodate a shoe or boot length that may not fall exactly on the 5 mm sizing increments, allowing a snug fit for all boot sizes. For example, the wire or rod configuration of bindings 13 and 14 seen in FIGS. 5-7 may provide such a benefit.

In certain embodiments the lower plate 2 has a front section 16 that may reproduce the shape of a DIN ski boot toe lug, hence allowing it to fit into a regular ski toe binding. “DIN” refers to Deutsches Institut für Normung (German Institute for Standardization). In certain embodiments, the lower plate 2 has a rear section 17 configured so it may reproduce the shape of a DIN ski boot heel lug, hence allowing it to fit into a downhill ski heel-binding. It will be appreciated that binding mechanisms other than DIN may of course be accommodated within the present linkage binding which serves as an insert between a downhill ski boot and a downhill ski binding of a downhill ski system (e.g., including downhill skis, downhill ski bindings on the skis, and downhill ski boots which are bindable into the downhill ski binding of the downhill skis). The system allows a user to insert the linkage binding between their downhill ski binding and their downhill skis, so that the linkage binding allows the boot to hinge upward from the toe while in the binding, as a user walks up a hill. Such a system may also be implemented in other analogous systems, such as a snow shoe binding, snow shoe boots, and snow shoes that work in an analogous manner. With typical downhill ski systems, when a user attempts to walk uphill, the binding of the boot in the ski's binding does not permit the heel of the boot to hinge upward from the toe (raising the heel up above the ski binding and ski), but the heel and toe both remain rigidly bound into the ski binding, forcing the user to lift the ski in order to lift the heel. The present linkage bindings allow the user to lift the heel without necessarily lifting the ski.

In certain embodiments, rear section 17 of lower plate 2 may be selectively repositionable relative to front section 16 so that lower plate 2 may replicate or accommodate the length of different sizes of ski boots. This can be important when the invention is used as an adapter, as downhill bindings are often mounted on to the ski spaced for a specific size ski boot. In certain embodiments, hinges 7, 8, 9 and 10 may be assembled from various components. Pin 10 (and or pin screw, bolt, or other fastener 10 a) may serve as a mechanism for securely attaching rear section 17 of lower plate 2.

In certain embodiments, mechanical limiting of the range of motion between upper plate 1 and lower plate 2 may be desirable. This function may be used to compensate for the angle of a hill while ascending. This may be accomplished via one or more lifters 18, 19 which may repositioned (e.g., rotated) to an upward position so that the upper plate 1 stops prematurely in its downward travel, before hitting lower plate 2. It may be possible to limit the range of motion by limiting the movement of the links 3 or 4 as well. For example, one or more stops may be provided on link 3 and/or link 4, limiting their movement. Examples of such function are shown in FIGS. 9a-9f As shown, the different lifters may provide different stop inclines, allowing the user to rotate upward the desired lifter, so as to serve as the desired stop. Lifters 18, 19 may be stowed in a cavity between plates 1 and 2 when not in use. In another embodiment the lifters or stops may be selectively removable from the linkage binding, allowing a user to install them, when their use is desired.

FIG. 6 shows an exemplary embodiment of a linkage binding 100 in relation to a standard downhill ski boot 200 coupled thereto.

FIG. 7 shows an exemplary embodiment of a linkage binding 100 with rear portion 17 disconnected from plate 2. This may allow for accommodation for different sizes of boots by lengthening or shortening the overall length of lower plate 2, using holes 22 and pins 10, 10 a, as described above.

FIGS. 8a-8b show an exemplary embodiment of a linkage binding in which top surface 5 of upper plate 1 may be configured with a toe binding 13 and a heel binding 14 and a selectively engageable clamp 15 so that a regular downhill ski boot may be removably and rigidly coupled to top surface 5. It will be apparent from the different illustrated toe and heel bindings shown in FIGS. 5-7 as compared to FIGS. 8a-8b that any conceivable toe or heel binding mechanism may be used. In certain embodiments, toe binding 13 and heel binding 14 may be adjustably releasable so they may disconnect from the boot in the event of a crash. In certain embodiments, the position of the heel binding 14 may be selectively relocated by the user so that a range of different size ski boots may be fit. In certain embodiments, lower plate 2 may be configured so it may be directly mounted (e.g., fixedly mounted) to a ski. In certain embodiments, it may be desirable to provide a selectively switchable lock between upper plate 1 and lower plate 2, thereby allowing the assembly to function as a free-heel uphill binding when unlocked, and a fixed-heel downhill binding when locked. In light of the present disclosure, it may be appreciated by those skilled in the art that a linkage between upper plate 1 and lower plate 2 can allow the movement to be tuned for a more ergonomic movement, better clearance of other binding components, and more efficient energy transfer between the ski boot and ski. In certain embodiments, upper plate 1 may feature a retractable brake 20 (FIGS. 8a-8b ) that lowers when a boot is removed, preventing runaway equipment.

The embodiment of FIGS. 8a-8b may include releasable bindings attached to upper plate 1, and lower plate 2 may be affixed directly (e.g., even permanently, non-releasably) to the ski. In this way, lower plate 2 may be incorporated into the ski. Such a configuration may be particularly useful for incorporating the described linkages into existing binding designs (e.g., a MARKER DUKE style binding). The present 4-bar linkages may be particularly beneficial over existing bindings, that do not provide as much versatility, and degrees of freedom of movement (e.g., as compared to a single pivot design).

FIG. 10 illustrates another embodiment of linkage binding 100 similar to that shown in FIGS. 5-7. Linkage binding 100 of FIG. 10 is shown as including more holes 23 a along the heel section of upper plate 1, and the center of upper plate 1 is open (as opposed to the planar surface seen in FIG. 5), so that upper plate 1 is a generally rectangular perimeter, that is open at its interior. Such a configuration may reduce the overall weight of the device. The additional holes 23 a may provide additional adjustability in where to couple heel binding 14 to upper plate 1. The toe section of upper plate 1 is also shown as including a plurality of holes 22 a, providing flexibility in where to couple toe binding 13 to upper plate 1.

Lifters 18 and 19 of FIG. 10 are also somewhat differently configured than those of FIGS. 5-7. For example, lifters 18 and 19 are shown as being formed from wire or rod metal material (e.g., stainless steel or aluminum) similar to bindings 13, 14. The rear of upper plate 1 may include a concavely curved or other cavity, into which a lifters 18 or 19 may be seated, against the lower surface of the cross-member 1 a of lower plate 1, limiting downward motion of upper plate 1 to no less than a desired angle formed between the lower plate 2 and upper plate 1 (e.g., no less than 5°, no less than 8°, no less than 10°, no less than 15°). It will be apparent that any desired lifter stop angle may be provided. The illustrated configuration may provide stops at about 8° and about 15°, allowing the user to select which lifter (if any) they desire to employ. The higher angle may be desired for a hill that is relatively more steep (e.g., generally speaking, no lifter may be used on downhill, or substantially horizontal, or only slightly inclined hills, the 8° lifter may be employed on more moderately inclined hills, and the 15° lifter may be employed on the most steeply inclined hills). Lifters 18, 19 of FIG. 10 flip between two positions, up or down. The lifters may be configured to snap between the up position and the down position, ensuring that the user appreciates what position has been selected. The wire lifters 18, 19 may flex slightly. Wire lifters 18, 19 may include a lower portion thereof that is engaged within an anchoring body 21. Each wire lifter 18, 19 may further include a lateral handle portion 25 which extends laterally sideways, outwardly, so as to be easily grasped by a user, desiring to flip a lifter 18 or 19 up, or down. Each lifter 18, 19 formed from elongate wire may simply rotate up or down within body 21. Each lifter may be configured to rotate independently of the other, if desired. A top portion 27 of each lifter 18, 19 may be shaped and sized for receipt into a cavity 29 in the rear of upper platform 1, while the cross-member 1 a across the rear of upper platform 1 may engage with top portion 27, with portion 27 being seated within cavity 29, against cross-member 1 a.

While the linkage bindings are principally shown in the context of a typical 4-bar linkage, it will be appreciated by those of skill in the art, that what is referred to a 4-bar linkage where one link of infinite length may also be provided. Such a linkage system may replace the front link with a slot within which the hinge pin or other hinge slides. Where there is no front link the system becomes a rigid triangulated assembly. The link is replaced with a slot that a pivot point (e.g., pin hinge 7′ is able to translate within, so that the system is still able to articulate. Such a configuration is sometimes referred to as an infinite length 4-bar linkage, even though only 3 members (the upper plate, the lower plate, and the rear link) are present, where the front link is replaced with a slot and a pin hinge sliding therein. In such an embodiment, the front of the upper plate may be directly connected to the front of the lower plate, using a single connection pin or other hinge (e.g., pin hinge 7′), sliding within slot 30. Such a configuration is illustrated in FIG. 11. Upper plate 1 may be rotationally coupled to hinge 7′ (e.g., a pin hinge). Upper plate 1 may also be rotationally coupled to the rear connecting link 4 via hinge 8 (e.g., a pin hinge). The lower plate 2 may be connected to upper plate 1 via a slot 30 that hinge 7′ translates within. Lower plate 2 may also be rotationally coupled to the rear connecting link 4 via hinge 10 (e.g., a pin hinge). From the above, it will be apparent that any of the 4 principle components (links and pin hinges) of the 4-bar linkage could be replaced by a translating movement at any of the pivot points. The particular arrangement shown in FIG. 11 is perhaps the most functional arrangement of such a modification. It will be appreciated that such an embodiment may otherwise include any of the components and/or features described in the context of any of the other embodiments described herein.

The present linkage binding inserts or adapters may be manufactured so as to be relatively lightweight, while also being robust and durable. For example, the plates and links may be formed from metal, such as a stainless steel (e.g., AISI 302 stainless steel). Bushings or lugs around hinges 7, 8, 9, and 10 may be formed of a high density polymer, such as polyoxymethylene (POM), high density polyethylene, combinations thereof, or the like. The pin hinges and other pins (e.g., pin 10 a), toe and heel bindings 13, 14, lifters 18, 19, or other components may be formed of metal (e.g., AISI 302 stainless steel or other metal). In an embodiment, the toe and heel bindings 13, 14 may be formed of stainless steel rod or wire. Even using such durable, high strength materials, the weight of the linkage binding inserts or adapters may be less than 1 kg each, or not more than about 800 g each (e.g., no more than about 3.5 lbs for the pair). Of course it will be appreciated that such weights are merely exemplary.

Without departing from the spirit and scope of this invention, one of ordinary skill can make various changes and modifications to the invention to adapt it to various usages and conditions. As such, these changes and modifications are properly, equitably, and intended to be, within the full range of equivalence of the following claims. 

1.-20. (canceled)
 21. A linkage binding for coupling a user's shoed or booted foot to another object, the linkage binding comprising: an upper plate including an upper surface to which a user's foot is to be secured; a lower plate including a lower surface to which another object is to be secured; a front connecting link hingedly attached to both the upper plate and the lower plate; and a rear connecting link hingedly attached to both the upper plate and the lower plate to form a 4-bar linkage; wherein the upper plate, the lower plate, the front connecting link and the rear connecting link form the 4-bar linkage, in which the lower plate remains substantially horizontal relative to a horizontal ground plane, the upper plate rotates rearward and upward about a pin connecting the front connecting link to the upper plate, and the upper plate rotates rearward and upward about a pin connecting the rear connecting link to the upper plate, so that the upper plate rotates along a portion of a substantially elliptical pathway during the walking motion of the user.
 22. The linkage binding of claim 21, wherein the lower surface of the lower plate of the linkage binding is attachable to at least one of a ski or snowshoe.
 23. The linkage binding of claim 21: wherein (i) the lower plate is incorporated into a ski or showshoe; or wherein (ii) the upper plate is incorporated into a ski boot or other footwear; or both (i) and (ii).
 24. The linkage binding of claim 21, wherein the front connecting link is attached to the upper and lower plates by pin hinges.
 25. The linkage binding of claim 21, wherein the rear connecting link is attached to the upper and lower plates by pin hinges.
 26. The linkage binding of claim 21, wherein the 4-bar linkage is one in which one of the connecting links is of infinite length, such that the front connecting link is a pin hinge that slides within a slot.
 27. The linkage binding of claim 21, wherein the upper plate includes a heel binding and a toe binding, wherein the bindings of the upper plate are selectively releasable, and wherein the lower plate is incorporated within a ski, and/or non-releasably affixed to the ski.
 28. A linkage binding for coupling a user's shoed or booted foot to another object, the linkage binding comprising: an upper plate including an upper surface to which a user's shoed or booted foot is to be secured, the upper plate including a selectively engagable heel binding at one end and a selectively engagable toe binding at another end; a lower plate including a lower surface to which another object is to be secured; a front connecting link hingedly attached to both the upper plate and the lower plate; a rear connecting link hingedly attached to both the upper plate and the lower plate at locations that are rearward relative to the front connecting link; during use, the upper plate and front and rear connecting links being configured to selectively allow the upper plate to rotate with and follow the user's shoed or booted foot as a user performs a walking motion while the lower plate remains substantially stationary relative to the object secured to the lower plate, so that the front and rear connecting links accommodate rotation of the upper plate upwards away from the lower plate as the user raises a foot during the walking motion, and so that the front and rear connecting links accommodate rotation of the upper plate downwards towards the lower plate as the user lowers the foot during the walking motion; wherein the upper plate, the lower plate, the front connecting link and the rear connecting link form a 4-bar linkage in which the lower plate remains substantially horizontal relative to a horizontal ground plane, the upper plate rotates rearward and upward about a pin connecting the front connecting link to the upper plate, and the upper plate rotates rearward and upward about a pin connecting the rear connecting link to the upper plate, so that the upper plate rotates along a portion of a substantially elliptical pathway during the walking motion of the user.
 29. The linkage binding of claim 28, wherein the lower surface of the lower plate of the linkage binding is attachable to at least one of a ski or a snowshoe.
 30. The linkage binding of claim 28, wherein the upper plate and the lower plate are substantially parallel to one another, with the upper plate over the lower plate when the user lowers the foot to the ground during the walking motion, and wherein the upper plate is inclined upward and moves rearward relative to the lower plate when the user raises the foot away from the ground during the walking motion.
 31. The linkage binding of claim 28, wherein the linkage binding is configured such that the lower plate remains substantially parallel to a substantially horizontal ground surface during the walking motion of the user.
 32. The linkage binding of claim 28, wherein the lower plate includes means for binding the lower plate to at least one of a ski or snowshoe.
 33. (canceled)
 34. The linkage binding of claim 28, wherein the linkage binding is adjustable to accommodate different sized shoed or booted feet of different users.
 35. The linkage binding of claim 28, further comprising one or more lifters which are selectively positionable to serve as stops limiting the downward range of motion of the upper plate towards the lower plate when a lifter is lifted to be engage with a bottom surface of the upper plate.
 36. The linkage binding of claim 35, wherein the linkage binding comprises at least two lifters, each providing a different stop angle between the upper plate and the lower plate, allowing the user to select which lifter and stop angle to use.
 37. A linkage binding configured as an insert between a downhill ski binding and a downhill ski boot of a downhill skiing system, the insert adapting the downhill skiing system for uphill travel by allowing the downhill ski boot to hinge upward from the toe while in the downhill ski binding of the downhill skiing system, the linkage binding comprising: an upper plate including an upper surface to which a user's shoed or booted foot is to be secured, the upper plate including a selectively engagable heel binding at one end and a selectively engagable toe binding at another end for binding the user's shoed or booted foot to the upper plate; a lower plate including a lower surface to which another object is to be secured, the lower plate including a selectively engageable heel binding at one end and a selectively engagable toe binding at another end for binding the lower plate to heel and toe bindings of the object to be secured to the lower plate; a front connecting link hingedly attached to both the upper plate and the lower plate; a rear connecting link hingedly attached to both the upper plate and the lower plate at locations that are rearward relative to the front connecting link; during use, the upper plate and front and rear connecting links being configured to selectively allow the upper plate to rotate with and follow the user's shoed or booted foot as a user performs a walking motion while the lower plate remains substantially stationary relative to the object secured to the lower plate, so that the front and rear connecting links accommodate rotation of a heel end of the upper plate upwards away from the lower plate as the user raises a foot during the walking motion, and so that the front and rear connecting links accommodate rotation of the heel end of the upper plate downwards towards the lower plate as the user lowers the foot during the walking motion.
 38. A method of providing and using a linkage binding as an insert between a user's booted foot and a downhill ski binding of a downhill ski, the method comprising: providing a linkage binding as recited in claim 37; inserting the linkage binding between the downhill ski binding of the downhill ski and the user's booted foot so that the toe of the user's booted foot is bound to the toe binding of the upper plate, the heel of the user's booted foot is bound to the heel binding of the upper plate, the toe binding of the lower plate is bound to the toe binding of the downhill ski and the heel binding of the lower plate is bound to the heel binding of the downhill ski; with the linkage binding inserted between the downhill ski binding of the downhill ski and the user's booted foot, lifting a heel end of the user's foot during a walking motion of the user in a manner that the heel end of the upper plate of the linkage binding is lifted off the lower plate, and upwards away from the heel binding of the downhill ski and the downhill ski for a first distance.
 39. The method of claim 38, wherein the toe end of the upper plate is also lifted off the lower plate and upwards away from the toe binding of the downhill ski and the downhill ski for a second distance, the first distance being greater than the second distance.
 40. The method of claim 38, wherein the linkage binding is inserted between the user's booted foot and the downhill ski binding of the downhill ski as the user walks up a hill, the method further comprising: removing the linkage binding from between the user's booted foot and the downhill ski after the user has walked up the hill; binding the toe of the user's booted foot into the toe binding of the downhill ski, and binding the heel of the user's booted foot into the heel toe binding of the downhill ski, and skiing down the hill without the linkage binding inserted between the user's booted foot and the downhill ski binding. 